The invention relates field of product recovery and the flushing of pipelines used in any fluid transfer operation and especially in piping systems utilized in the filling of containers, including bottling lines, can lines and tank filling operations. More specifically, the present invention provides a method and apparatus for a pipe pig that is formed from a substantially frozen product or a component of the product.
Typically, the transfer of liquid materials or products demands a periodic purging or flushing of the pipe carrying the materials. This pipe may be above or below ground, or in a plant setting. Often, a particular piping system must have the ability to handle a wide variety of products or at least periodic changes in product composition. These various products may differ in terms of their viscosity, ranging from high viscosity products such as peanut butter, salad dressings, and frozen concentrated juices; medium viscosity products, such as pharmaceutical products, petroleum products, syrups, oils, soups, stews, and sauces; to low viscosity products such as wine, waters and juices. These products also vary in terms of other properties, such as temperature, pH and suspended solids. Another such property is the presence or absence of carbonation.
The purging of a piping systems results in lost product unless a system of xe2x80x9cproduct recoveryxe2x80x9d is employed. Current product recovery systems are burdened with serious problems. For piping systems, the xe2x80x9cproduct recovery problemxe2x80x9d usually means that periodically, a significant quantity of product in the piping system becomes waste that cannot be economically recovered for later use. The product recovery problem typically arises in several situations with piping system designs. For example, if a piping system is used to fill tanks or containers with a variety of different products over the course of a day or a week, then each time a run for one product ends and a run for a different product begins, a considerable amount of both products becomes unrecoverable waste. Food grade piping systems handle a considerable amount of perishable products, such as carbonated products, which must be maintained at a constant temperature, especially during a bottling or container filling process. Also, pharmaceutical and technical grade products require special handling to ensure product integrity or purity. Any compromise in this purity or control translates to unrecoverable waste at, the end of each work day, or product change or alteration.
Regrettably, much of the unrecoverable product waste currently created by the liquid material processing industry is often literally dumped down the drain, or is stored in tanks or drums to later be reprocessed, taken to a landfill, or, for certain potentially hazardous products, to an appropriate hazardous waste disposal facility. In the case of food and beverage products, this unrecoverable waste is most often dumped down the drain. The xe2x80x9cdrain dumpingxe2x80x9d disposal method costs the processor more than just the value of the wasted product, because this wasted product must be treated before it is reintroduced back into the environment.
For those food processors without their own waste water treatment facility, the liquid waste product dumped into the drain travels through the sewage system to the local sewage treatment facility. The high sugar or carbohydrate content of most wasted food products then causes a population explosion in the bacteria at the sewage treatment facility. The bacteria used by sewage treatment facilities is xe2x80x9caerobicxe2x80x9d bacteria, which means they use up oxygen as they consume sewage waste. Sewage treatment plants maintain a careful balance between their bacteria""s population and the incoming sewage waste, to ensure adequate oxygen for their bacteria to survive. Sewage treatment plants make every effort to ensure that their entire system remains aerobic (with oxygen) rather than anaerobic (without oxygen). Aerobic bacteria do not create offensive odors when they consume sewage waste. Anaerobic bacteria create offensive odors, and are less efficient than aerobic bacteria at disposing of sewage waste. Sewage treatment plants track precisely how much high sugar content industrial waste is dumped into their system, and they charge each company dumping this waste a considerable xe2x80x9cbiological oxygen demandxe2x80x9d (BOD) assessment, which can significantly impact profit.
Sewage treatment plants also track precisely the quantity of suspended solids contained in the waste stream they receive from industrial sources, because the required treatment of these suspended solids is expensive. Suspended solids are present in unfiltered fruit juices, soups, sauces, peanut butter, condiments, and a wide variety of other products. In addition to a monthly B.O.D. assessment, sewage treatment plants also charge their industrial sewage sources a monthly suspended solids assessment.
For those processing companies that elect to build their own waste water treatment facility, they must incur the expense of building, maintaining, and operating their own facility. This cost, which can be considerable, is often incurred primarily because of their decision to dump wasted product down the drain. Accordingly, there is a great need for solutions to the problem of product recovery.
The invention provides a method and apparatus for pipe pig that is employed in a piping system for recovering a product. Specifically, the present invention provides a pipe pig or simply referred to as a xe2x80x9cpigxe2x80x9d and a method of utilizing the pipe pig as an instrument to flush or purge the piping system, which is includes a pipe that is normally filled with a product stream. The pig is a substantially solid slug in the flow of the pipe. The pipe pig includes at least a component of a product stream and the pig is at least partially frozen to achieve its substantially solid form.
A preferred method of the invention includes providing the pipe pig within a launch chamber. The launch chamber has a junction with a pipe. The pipe conducts the product stream past the launch chamber. The pipe pig, as provided within the launch chamber, is substantially frozen and formed from at least a component of the product stream.
A release valve is opened to allow the pipe pig to enter the pipe of the product. Preferably, the release valve is normally closed to partition the launch chamber from the pipe. The release valve is positioned proximate the junction between the launch chamber and the pipe of the product stream. An exterior surface of the launch chamber can be heated to prevent the pipe pig from sticking within the launch chamber when the pipe pig is released into the pipe containing the product stream.
The pipe pig can be either be propelled into the product stream, or allowed to fall by gravity or suction alone. One alternative that can be utilized to propel the pipe pig into the pipe of the product stream is to blow a quantity of an agent into the launch chamber. Additional quantities of the agent can be blown into the launch chamber to further propel the pipe pig within the pipe of the product stream. Blowing the agent into the launch chamber can be utilized to form a slug of agent in the pipe of the process stream, behind the pipe pig.
Articulations can also be formed into the pipe pig. These articulations preferably include slots into the pipe pig. The articulations allow the pipe pig to bend along the length of the pipe pig and so allow the pipe pig to travel around elbows and bends in the pipe.
The pipe pig can be formed external to the launch chamber by freezing a liquid to form the pipe pig and loading the pipe pig into the launch chamber through a chamber access. To prevent the pipe pig from prematurely entering into the pipe from the launch chamber, and also to prevent the product stream from entering the launch chamber and exiting through the chamber access, a released valve located proximate the junction between the launch chamber and the pipe is closed prior to loading the pipe pig into the launch chamber.
In a preferred alternative, the pipe pig can be formed from a semisolid ice material. The semisolid ice material contains at least a component of the product stream. The semisolid ice material is introduced into the launch chamber after closing the release valve. The semisolid material can be formed by first substantially freezing at least a component of the product stream to form a frozen material. The frozen material is then shaved, or in some similar method, reduced into particles of a size that can be introduced into the launch chamber. In this way, the shaved frozen material forms the semisolid ice material.
The pipe pig can be formed within the launch chamber from a liquid, the liquid being at least a component of the product stream. The liquid is substantially frozen within the lunch chamber to form the pipe pig. The freezing of the liquid is preferably accomplished by refrigerating an exterior surface of the launch chamber. Articulations can also be formed along the length of the pipe pig while the pipe pig is formed within the launch chamber. To form articulations into the pipe pig, a plurality of opposed valves are positioned along the length of the launch chamber. This plurality of opposed valves are partially closed prior to freezing the liquid in the launch chamber. The plurality of opposed valves are then opened after the freezing of the liquid. To aid in opening the plurality of opposed valves, heat can be applied to the plurality of opposed valves prior to the opening them.
In a preferred alternative method of forming the pipe pig, a quantity of a super-cooled freezing agent is injected into the pipe that contains the product stream. The freezing agent substantially freezes a portion of the product stream, to form the pipe pig. A propelling agent can then be injected into the pipe of the product stream to propel the pipe pig through the pipe. A filling agent can be injected into the pipe of the process stream to form a slug of the filling agent in the pipe, behind the pipe pig.
The present invention can be employed in the food, beverage and pharmaceutical industries, as well as in the processing of petroleum products, chemicals or water, and can be utilized for product recovery in any material handling operation that includes a pipe transfer of a flowable product.
An object of the invention is that the pipe pig is employed as an instrument for product recovery in a piping system. The use of the pipe pig in this way has the advantage of minimizing product losses during product change-out or interruption that would conventionally result in the loss of a significant quantity of product that must be used to flush the pipe line. With product recovery using the pipe pig method of the present invention, the amount of waste product that must be discarded from a piping system when the system is shut down, or a change is made from one product to another, is minimized.
An additional advantage of the invention is that the pipe-pig is formed from at least a component of the process stream flowing within the pipe. This eliminates the need to retrieve the pig from the system. The frozen pipe pig simply melts when it reaches its destination or if it becomes inadvertently lodged within the pipe.
The invention will be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.